The Polymerase Chain Reaction will be used to analyze DNA sequences in single human sperm. The ability to study large numbers of meiotic products from single individuals will allow the construction of human genetic maps at a resolution which far exceeds that possible by using conventional pedigree analysis. Sperm will be isolated using flow cytometry. The efficiency of sperm lysis and PCR amplification will be maximized under conditions which minimize contamination. The immediate goal is to be able to routinely achieve a level of resolution for genetic mapping of less than 0.1 cM (0.001 recombination fraction). Accomplishment of this goal will allow three point crosses to be used to order very closely linked markers. The relationship between physical distance and recombination frequency could also be investigated. The development of this single sperm technology may have a significant impact on mapping the human genome.